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The paper considers the thermo-mechanical mechanism of interaction between the damage agents and armor protection made of polymer fabrics. A simplified mathematical model is proposed to describe the deceleration of a damage agent within an armor fabric due to the dissipation of energy expended on irreversible stretching deformations of fabric fibers, as well as fiber slipping friction and material heating. Woven fabric layers are replaced by solid layers characterized by averaged stiffness and viscosity. A discrete numerical model of a solid material is proposed to reduce a problem with a finite number of degrees of freedom; motion equations are obtained on the basis of the Lagrange equations of the second kind, and for their integration, a stable non-conservative difference scheme is used. The software implementation is based on a functional-object paradigm which allows the modeling of conjugated processes. The parameters of governing equations are identified by using the experimental data. Some illustrative examples of interaction between damage agents and armor barriers with different arrangement of fibers are presented. The proposed model can be used to predict the quality of armor protection with the changing number and location of fibers, as well as to test the armor protection by applying the technique of infrared thermography.

Analysis of internal defects in the structure of composite objects can be based on the study of dynamic temperature fields, the patterns of variation of which reflect the location of heat sources. For example, acoustic ones, under external influences, determination of the location of thermal field sources (internal defects) – thermal tomography – presents in this approach, in general, the problem of identifying the model of heat propagation in a plate. This paper describes a method and technical means for determining the depth of occurrence of internal defects in composite structures by analyzing the temperature fields on two surfaces of a product to be created by an internal heat source, which is a defect, and by formed mechanical action on it, for example, ultrasonic mechanical vibrations (ultrasonic thermotomography). Experimental studies of the previously theoretically proved method of thermal tomography in the presence of an internal heat source have been carried out. As a research object, a plate of composite material – pressed fabric-based laminate- was considered. To simplify the experimental studies and increase the reliability of the results, the internal heat source was modeled with a nickel-chromium spiral to be heated by an electric current. The nickel-chromium spiral was laid in the plates when their pressing (manufacturing) at various occurence depths relative to surfaces of the plates. The experimental investigation technique is described. It is experimentally shown that the proposed method allows the occurence depth of defects in a composite material to be determined. Fault in the depth determining of the defects occurrence depends on the depth value and does not exceed 10 % of the thickness of the controlled article that is acceptable for the practical use.

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